Linux Device Drivers 3 examples

1 files changed, 71 insertions, 0 deletions

diff --git a/sbull/sbull.h b/sbull/sbull.h
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+
+/*
+ * sbull.h -- definitions for the char module
+ *
+ * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
+ * Copyright (C) 2001 O'Reilly & Associates
+ *
+ * The source code in this file can be freely used, adapted,
+ * and redistributed in source or binary form, so long as an
+ * acknowledgment appears in derived source files.  The citation
+ * should list that the code comes from the book "Linux Device
+ * Drivers" by Alessandro Rubini and Jonathan Corbet, published
+ * by O'Reilly & Associates.   No warranty is attached;
+ * we cannot take responsibility for errors or fitness for use.
+ *
+ */
+
+
+#include <linux/ioctl.h>
+
+/* Multiqueue only works on 2.4 */
+#ifdef SBULL_MULTIQUEUE
+#    warning "Multiqueue only works on 2.4 kernels"
+#endif
+
+/*
+ * Macros to help debugging
+ */
+
+#undef PDEBUG             /* undef it, just in case */
+#ifdef SBULL_DEBUG
+#  ifdef __KERNEL__
+     /* This one if debugging is on, and kernel space */
+#    define PDEBUG(fmt, args...) printk( KERN_DEBUG "sbull: " fmt, ## args)
+#  else
+     /* This one for user space */
+#    define PDEBUG(fmt, args...) fprintf(stderr, fmt, ## args)
+#  endif
+#else
+#  define PDEBUG(fmt, args...) /* not debugging: nothing */
+#endif
+
+#undef PDEBUGG
+#define PDEBUGG(fmt, args...) /* nothing: it's a placeholder */
+
+
+#define SBULL_MAJOR 0       /* dynamic major by default */
+#define SBULL_DEVS 2        /* two disks */
+#define SBULL_RAHEAD 2      /* two sectors */
+#define SBULL_SIZE 2048     /* two megs each */
+#define SBULL_BLKSIZE 1024  /* 1k blocks */
+#define SBULL_HARDSECT 512  /* 2.2 and 2.4 can used different values */
+
+#define SBULLR_MAJOR 0      /* Dynamic major for raw device */
+/*
+ * The sbull device is removable: if it is left closed for more than
+ * half a minute, it is removed. Thus use a usage count and a
+ * kernel timer
+ */
+
+typedef struct Sbull_Dev {
+   int size;
+   int usage;
+   struct timer_list timer;
+   spinlock_t lock;
+   u8 *data;
+#ifdef SBULL_MULTIQUEUE
+   request_queue_t *queue;
+   int busy;
+#endif
+}              Sbull_Dev;